DESCRIPTION: The research in this proposal is intended to elucidate the role of zinc in childhood growth and development and the effects of zinc deficiency on childhood morbidity. In addition, the proposal is intended to develop new methodology for the analysis of longitudinal data in large field trials where morbidity outcomes are variable and there are time varying outcomes associated with child growth and development. The objectives will be met by analyzing data from two large control trials on zinc supplementation and specifically analyzing the effects on outcomes such as infectious diseases, morbidity, growth and development. A direct comparison of newer methods of analysis with more traditional ones will be employed in order to develop the most appropriate approach for investigating substantive hypotheses regarding the potential impact of zinc supplementation on childhood infectious illness, immunologic competence, growth, motor and cognitive development. These studies may contribute to our understanding of the role of zinc deficiency in childhood which may be of particular importance to specific high risk groups and may help determine the nutritional educational guidelines for zinc fortification of foods in developing countries.